I have had Urticaria Pigmentosa (UP), a form of mastocytosis, since in my late twenties (I am now 65), which my consultant assures me is cutaneous, not systemic. However, the spots each year get gradually worse, especially on the outer thighs, where they now look almost like strawberry marks as the spots are joining together. Once the spots appear, they become permanent. Nothing special seems to trigger the spots appearing, and there is no family history of the condition. The spots get itchy after a hot bath, or sitting in the sun, but usually the itching dies down if I leave the spots alone, otherwise I do not have any other symptoms, such as digestive problems. I have anti-histamine to take if needed, but rarely need it.
[urticaria pigmentosa, UP, skin spots, reaction to heat, adult]